🟠 DupliMark

DupliMark is a lightweight Visual Studio Code extension that highlights duplicate variable and function declarations in your JavaScript and JSX code. It helps you catch accidental re-declarations early and keeps your code clean and bug-free.

✨ Features

🔍 Real-time detection of duplicate let, const, var, function, and arrow function declarations
✅ Highlights both exports.name and module.exports.name
🧠 Skips built-in globals like console, setTimeout, etc.
🎯 Underlines only declarations (not usages) with a subtle orange border
🟧 Highlights are non-intrusive, ideal for focused development

📂 Supported File Types

Language	Extensions
JavaScript	`.js`
JavaScript React	`.jsx`

TypeScript support coming soon.

📸 DupliMark Examples

Examples of duplicate variable and function declarations that DupliMark will highlight in your JavaScript/JSX code.

❗ Duplicate Variables

const name = 'Ajith';
let name = 'Arun'; // ⛔ Duplicate declaration detected

let user = 'Ajith';
let user = 'Arun'; // ⛔ Duplicate let

const id = 101;
const id = 102; // ⛔ Duplicate const

var age = 25;
var age = 30; // ⛔ Duplicate var

❗ Mixed Declaration Types (Still Duplicate)

let email = 'ajith@example.com';
const email = 'arun@example.com'; // ⛔ Duplicate variable name across different types

var token = 'abc123';
let token = 'xyz456'; // ⛔ Duplicate name using var + let

❗ Duplicate Functions

function getName() {
  return 'Ajith';
}

function getName() {
  return 'Arun'; // ⛔ Duplicate function name detected
}

✅ What It Detects

Pattern	Example	Detected
Same variable redeclared	`let x; let x;`	✅ Yes
Mixed declaration styles	`const x; var x;`	✅ Yes
Arrow vs regular function	`const x = () => {}; function x() {}`	✅ Yes
Exports vs local function	`exports.x = () => {}; function x() {}`	✅ Yes
Usage only (no new declaration)	`console.log(x);`	❌ No
Scoped variables (in different blocks)	`if (true) { let x = 1; } let x = 2;`	❌ No

🚫 Not Highlighted

const email = 'user@example.com';
console.log(email); // ✅ Just usage

function greet() {
  const email = 'internal@example.com'; // ✅ Block-scoped, allowed
}

🚀 Getting Started

Install from VS Code Marketplace:

Open Visual Studio Code
Go to the Extensions Panel
Search for: DupliMark
Click Install

Or install via CLI:

code --install-extension duraiDev.duplimark

🔧 Configuration

No configuration required. It works out of the box on .js and .jsx files.

🧪 Planned Features

[ ] TypeScript & TSX support
[ ] Rename/fix suggestions
[ ] Customizable highlight styles
[ ] Multi-scope detection

🧑‍💻 Author

Built with ❤️ by [Durai Raja]

Found a bug or have suggestions? Open an issue or submit a pull request!

📬 Feedback

If you like DupliMark, don’t forget to ⭐️ the extension on the Marketplace and share it with your team!

Duplicate Highlighter

Durai Raja